how to build a variable for current datamonth

[#1]

i need to pull the data from database for the current data month - 2 so for this i need to automate the process

so in the script i need to give month= 8/01/2013  this should change every month

can any one help me in building the variable

thanks in advance

[Clever_Anjos]

Yes, it´s an example of incremental load based on a DateTime